Conductive bridge random access memory (CBRAM) cells (sometimes referred to programmable metallization cells (PMCs), may switch between impedance states in response to the application of a voltage or current. CBRAM cells may switch between states through mobile ions formed in an ion conductor layer. An ion conductor layer may be formed between an “active” electrode and an “indifferent” electrode. An active electrode may be a source of conductive ions. An indifferent electrode may not be a source of conductive ions.
FIGS. 24A to 24D show a conventional method of forming a CBRAM cell 2400.
FIG. 24A shows the formation of a bottom electrode 2402 on a surface 2404. A bottom electrode 2402 is an “indifferent” electrode. A surface 2404 is typically formed from an insulating material. A bottom electrode 2402 may be formed within an insulating layer 2406. An opening 2408 in the insulating layer 2406 exposes the bottom electrode 2402. Bottom electrode 2402 does not serve as a source for conductive ions for a subsequently formed ion conductor layer.
FIG. 24B shows the formation of an ion conductor layer 2410 over and in contact with bottom electrode 2402. A top electrode 2412 is formed on ion conductor layer 2410. A top electrode 2412 may be an active electrode, and thus may be a source of conductive ions for ion conductor layer 2410.
FIG. 24C shows an ion incorporation step. Light (e.g., UV light), may be applied and conductive ions from top electrode 2412 may be incorporated into ion conductor layer 2410.
FIG. 24D shows a cap layer 2414 formed on a surface of top electrode layer to keep the top electrode material from reacting with exposed ambient in subsequent device processing.